Railway signaling apparatus



In l llll R. DELL RAILWAY SIGNALING APPARATUS Filed March 7, 1923 INVENTOR:

BY Q a A L ATTORNEY n1 l v WTHTI mm I III Sept. 14, 1926.

IIHHI Patented Sept. 14, 1926.

PATENT OFFICE.

RAILWAY SIGNALING APPARATUS.

Application filed March 7, 1923, Serial No. 623,533, and in Great Britain March 18, 1922.

This invention relates to si 'naling systems for railways and the like of the kind comprising light signals constituted by electric lamps operated by alternating or pulsating electric currents.

The invention has for its-object to provide improved apparatus of this character in which the signal lamps giving a danger and clear indication respectively are arranged to be rendered operative alternately without interrupting the circuits through which. either of these lamps is supplied with operating current.

ccording to the present invention this action is attained by the provision of a special transformer interposed between the source of supply of current for the signal lamps and the circuits in which these lamps are connected,the transformer being adapted to cause current to be supplied to one or other of the signal lamps by varying the distribution of the magnetic flux within the transformer core.

The invention is illustrated in the accom panying drawings, of which Figs. 1, 2 and 3 are diagrammatic views of various forms of special transformer which may be employed showing the con nections and general arrangements of the windings thereof.

Referring now to the system shown diagrammatically in Fig. 1 it will be seen that the apparatus consists of a laminated iron core having three limbs A, B and 0. Upon the centre limb B a coil of insulated wire D is wound, which coil is connected permanently to the alternating current supply mains P. The current flowing in this coil will induce a flux in the iron core, and considering a particular instant of time, the direction of flux in the cores would he, say

. upwards in the centre limb B, dividing and part traveling downwards in each of the outer limbs A and C. On the limbs A and C, two coils E and F are wound. These coils will have electro-motive forces induced in them by the flux traversing the cores, and

the coils are so connected that the electromotive forces aid each other thusproducing a current through the red lamp Upon the limbs IA and C are also wound coils Hand JL': These coils electro-motive"forces induced" in them, but they "are connected. So that the electro-rno will also have tive forces are in opposition and thus no current is produced in the green lamp K.

It will be understood that the number of turns in coils H and J must be in inverse ratio to the fluxes in the respective limbs of the transformer in order that the coils H and J may give equal and opposite electromotive forces under danger conditions.

Upon the limb A a coil L is wound. hen the signal is required to show clear this coil is energized, for instance, by the action of track relay indicated at O.

Coil L is arranged to produce a flux of the same magnitude as D. Considering the fluxes in the limbs now at a particular instant of time. There will be a flux travelling upward in limb A and another travelling upward in limb B, these combining and returning downward through limb C.

It will be seen that the electro-motive forces induced in coils E and F will now be in opposition, the direction of the electromotive force in coil E having reversed.

N. At the same time the electro-motive force in the coil H is also reversed, so that the electro-motive forces in H and J now aid each other and produce a current through lamp K.

The coil M has less turns than L and is connected in opposition with L. This is for the purpose of preventing coil L feeding back on to the line in case of a fault developing in the cable.

Referring now to Fig. 2 a modified arrangement is illustrated in which the coils E, F are provided with extensions Q, B, respectively of their windings, these coil extensions being connected to indication conductors S leading to any suitable type of indication apparatus at a remote point, such, for instance, as a signal cabin.

s It will be understood that when the coils E and F are co-operating to transmit current to the signal lamp N a higher electromotive force will be impressed upon the indication conductors S and thus cause an indication to'be given that the lamp N is il- 'luminated. V

Referring now to Fig. 3 the invention is illustrated as applied to signal apparatus adapted to give three different indications, this apparatus comprising three signal lamps indicated at W, T and U, respectively.

There is therefore no current through lamp Two: special transformers are employed, each similar to the transformer shown in Fig. 1, and having cores A, B and G, and A, B, C, respectively, and windings D, E,

F, etc., and D,.E, F, etc., respectively.

The transformer winding D is permanently connected to the supply main P and gencrates fluxes traversing the cores which induce electro-motive forces in the coils E, l1"

which co-operate'to cause current to'traverse the danger signal lamp V, the electro-motive forces generated in the coils H, J, opposing one another so .that current is not supplied to the coil D of the second transformer to lo which the coils H, J are connected. Consequently, the signal lamps T, U which are connected to'the coils E, F and H, J on the:- second transformer are both inoperative.

Intheevent of the-track section ahead of thetsection controlled by the signaling apparati'isibeing unoccupied by a train or vehiclepthe-coil L is energized'bythe action of a trackrelay O, so' that 'tl'ie'direction of the fluxtraversing the'coils E and H is reversed.

The coils E, F, consequently oppose one another and the signal lamp N is extinguished WlifilflSthQ'COilSIl, J assist one another and currentissupplied to the coil D of the second transformer;

illuminated by current from the coils E, F

assisting; one another and a caution indication is'givenv In the event ofthcinentadjacent track section ahead being also-unoccupied the track 05: relay. contact V is closed and current supplied-to the coil L. The direction of the flux traversing the coils d andH: is thus reversed: and the" lamp 1* is extinguisl'ied and current supplied to'the'lamp U from the 4O coils H, J which now assist one another,

thus givingaa safety: indication.

The invention is-notlimited to the particular relative arrangements of the various windings upon-the limbs of the transformer core as above described and-any equivalent arrangement'mayobviously be adopted.

Having. now particularly described andascertained thenature of my said invention, and in what manner the same is to be perfio formed, I declare that what I. claim is 1. Incombination, a signal comprising electric-lamps, a source of alternating current, a transformer interposed between said source and said-lan'ips, and means for varying the distribution of magnetic flux-in the core .jofsaid transformer to selectively supply current to said lamps. A

QMIn combination,, a signal comprising electric lamps; a source. of alternating; curca rent, a transformer interposed between said son-ree and said lamps, and having. a, pluralfor-v r yin said-lamps;

The lamp T is therefore y ni-ultiple i-andmeans2 -dlgtlllotltmn ofim-agneticfiux nasal pathsi o? selectively; supply ,1 current] to 3. 1nccmbination, a signal comprising electric lamps, a source of alternating current, a transformer energized from said source, acircuit for one lamp including. a pair. of transformer windings connected in series to oppose each otherv under the normal condition of flu; distribution in said transformer, a circuit ror another lamp including a pair of transformer windings connected in series toassist each other under the normal condition of flux distribution in said transformer, and means for varying the distribution offfliix in said transformer.

l. In combination, a signal comprising electric lamps, a-source of alternating current, a transformer energized from said source, a circuit for one. lamp/including a pair of transformer windings connected 'in Series to oppose each otherunderfthe normal condition of. flu);v distribution in said transformer, a'circuit foranotherlamp including .a pair .of transformer windings con nected in; series to assist each other :underthe normal condition of flux distribution in said transformer, and 'an: additional'winding on said transformer arranged when'energized to reverse the relative direction'of the flux traversing the core limb carrying one winding fcr eachwlamp.

5. In combination, a signal comprising electric lamps, ZLbSOlll'CG :ofialternatin g C111 rent, a transformer energized from said source, a circuit'f-or one lampincluding a pair of transformer windings connected in series to oppose each other under the normal condition of il-uxsdistribution in said tra'ns former, a. circuit. fori another lamp. includ ing. a pair of transformer windings con nectedlin seriestonssist each other under the normal condition :of flux distribution in said transformer, the windings included in oneio fsaid damp circuits being extended to supplycurrent'to an indication circuit, and meanszfoix varying thedistributionof flux in said transformer;

(bin combination, a signal comprising electric lain.ps, a= magnetizable core comprisingthreeparallel limbs, a primary windingxlocatedon the: middle limb, a circuit for onelamp including two-windings located on thetwo outerlimbs-respectively and so connected that the voltages induced therein due tozliux created by said primarywinding oppose each other, a circuit for another lamp including two windings located on said outer limbs respectively: and so connected that. the voltages: induced therein due to flux created by said primary winding assisteach other, and'mea-ns -for varying. the CllSfilllEHtiOlFLOfl'tllB flux in said outer limbs due to said. primary winding;

7. In. combination,. a signal comprising electric; lamps,-.a @inagnetizable icore comprisingthree parallel limbs; at-priniaryi winding locatedaon the inid'd lealiinb aacircuit -for one lamp including two windings located on the two outer limbs respectively and so connected that the voltages induced therein due to flux created by said primary winding oppose each other, a circuit for another lamp including two windings located on said outer limbs respectively and so connected that the voltages induced therein due to flux created by said primary winding assist each other, a second primary winding on one of said outer cores arranged to create in such limb a magnetic flux which opposes the flux therein due to the first primary winding, and means for controlling the su ply of alternating current to one of said primary windings.

8. In combination, a signal comprising electric lamps, a magnetizable core comprising three parallel limbs, a primary winding located on the middle limb, a circuit for one lamp including two windings located on the two outer limbs respectively and so connected that the voltages induced therein due to flux created by said primary winding oppose each other, a circuit for another lamp including two windings located on said outer limbs respectively and so connected that the voltages induced therein due to flux created by said primary winding assist each other, a second primary winding on one of said outer cores arranged to create in such limb a magnetic flux which opposes the flux therein due to the first primary winding, and means for constantly supplying alternating current to one of said primary windings and i for at times supplying alternating current to the other of said primary windings.

In testimony whereof I afiix my signature.

ROBERT DELL. 

